Abstract

Health beneficial effects of xanthohumol have been reported, and basic research provided evidence for anti-cancer effects. Furthermore, xanthohumol was shown to inhibit the migration of endothelial cells. Therefore, this study investigated the anti-metastatic potential of xanthohumol. MCF-7 breast cancer spheroids which are placed on lymphendothelial cells (LECs) induce “circular chemorepellent-induced defects” (CCIDs) in the LEC monolayer resembling gates for intravasating tumour bulks at an early step of lymph node colonisation. NF-κB reporter-, EROD-, SELE-, 12(S)-HETE- and adhesion assays were performed to investigate the anti-metastatic properties of xanthohumol. Western blot analyses were used to elucidate the mechanisms inhibiting CCID formation. Xanthohumol inhibited the activity of CYP, SELE and NF-kB and consequently, the formation of CCIDs at low micromolar concentrations. More specifically, xanthohumol affected ICAM-1 expression and adherence of MCF-7 cells to LECs, which is a prerequisite for CCID formation. Furthermore, markers of epithelial-to-mesenchymal transition (EMT) and of cell mobility such as paxillin, MCL2 and S100A4 were suppressed by xanthohumol. Xanthohumol attenuated tumour cell-mediated defects at the lymphendothelial barrier and inhibited EMT-like effects thereby providing a mechanistic explanation for the anti-intravasative/anti-metastatic properties of xanthohumol.

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Acknowledgments

We wish to thank Toni Jäger for preparing the figures and to Prof. J. Ulrichova for kind gift of HUVEC cells. Further, Grant Nos. GACR (P505/11/1163) and ED0007/01/01 (both to M.S.) from the Centre of the Region Haná for Biotechnological and Agricultural Research, a grant of the Fellinger foundation (to G.K.), grants of the Herzfelder family foundation (to T.S., H.D., P.S. and M.G.), a grant of the “Hochschuljubilaeumsstiftung der Stadt Wien” grant number H-2498/2011 (to P.S.), a scholarship from the Austrian exchange service OeAD (to K.J.), and grants by the Austrian Science Fund, FWF, grant numbers P19598-B13 and P20905-B13 (to W.M.), S10704-B03 and S10704-B13 (to V.M.D.) and by the European Union, FP7 Health Research, project number HEALTH-F4-2008-202047 (to W.M.) are gratefully acknowledged.